Hormones, Amino Acids Altered by Gastric Bypass Surgery
Model allowed simulation of preoperative condition and postoperative situation in the same patient
FRIDAY, May 10 (HealthDay News) -- Gastric bypass surgery alters the hormones and amino acids produced during digestion, possibly elucidating the mechanisms through which the surgery eliminates symptoms of type 2 diabetes, according to a study published in the May issue of the Journal of Clinical Endocrinology and Metabolism.
Andreas Lindqvist, Ph.D., from Lund University in Malmö, Sweden, and colleagues first gave four patients a mixed meal test (MMT) orally, preceded by overnight fast, and then gave it to them via the gastrostomy tube, preceded by two-hour fasting. Hormones and metabolites were assessed from blood samples.
The researchers found that the oral MMT produced a 4.6-fold increase in plasma insulin, a 9.3-fold increase in glucagon-like peptide-1, and a 2.5-fold increase in glucose-dependent insulinotropic peptide plasma levels (P < 0.05 for all), compared to the gastrostomy MMT. Elevated branched-chain amino acid levels (1.4 to 2-fold; P < 0.05) and suppressed fatty acid levels (approximately 50 percent; P < 0.05) accompanied the changes in hormone levels.
"These data, comparing identical nutrient delivery, demonstrate markedly higher incretin and insulin responses after oral MMT than after gastric MMT, thereby providing a potential explanation for the rapid remission of type 2 diabetes observed after gastric bypass surgery," the authors write.